From: Wataru Noguchi Date: Sat, 05 Oct 2013 11:39:58 GMT Subject: Re: [PATCH] mingw-multibyte: fix memory acces violation and path length limits. Message-ID: <524FFA8E.70009@gmail.com> In-Reply-To: Hi, I put following printf logs. int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *topath) { static char path[PATH_MAX + 1]; struct stat st; int len = state->base_dir_len; if (topath) return write_entry(ce, topath, state, 1); memcpy(path, state->base_dir, len); fprintf(stderr, "path: %s\n", path); fprintf(stderr, "len: %d\n", len); strcpy(path + len, ce->name); len += ce_namelen(ce); fprintf(stderr, "path: %s\n", path); fprintf(stderr, "len: %d\n", len); fprintf(stderr, "path_max: %d\n", PATH_MAX); -------------------------------------------------------------------------------------- crash result wnoguchi@WIN-72R9044R72V /usr/tmp (master) $ git clone https://github.com/wnoguchi/mingw-checkout-crash.git a2 Cloning into 'a2'... remote: Counting objects: 8, done. remote: Compressing objects: 100% (7/7), done. remote: Total 8 (delta 0), reused 8 (delta 0) Unpacking objects: 100% (8/8), done. Checking connectivity... done path: len: 0 path: dummy 1-long-long-long-dirname/dummy 2-long-long -long-dirname/dummy 3-long-long-long-dirname/dummy 4-l ong-long-long-dirname/dummy 5-long-long-long-dirname/aaaaaaaaaaaa.txt len: 302 path_max: 259 crash!! -------------------------------------------------------------------------------------- build with CFLAGS = -g -O2 -fno-inline-small-functions -Wall wnoguchi@WIN-72R9044R72V /usr/tmp (master) $ git clone https://github.com/wnoguchi/mingw-checkout-crash.git a3 Cloning into 'a3'... remote: Counting objects: 8, done. remote: Compressing objects: 100% (7/7), done. remote: Total 8 (delta 0), reused 8 (delta 0) Unpacking objects: 100% (8/8), done. Checking connectivity... done path: len: 0 path: dummy 1-long-long-long-dirname/dummy 2-long-long -long-dirname/dummy 3-long-long-long-dirname/dummy 4-l ong-long-long-dirname/dummy 5-long-long-long-dirname/aaaaaaaaaaaa.txt len: 302 path_max: 259 Warning: Your console font probably doesn't support Unicode. If you experience s trange characters in the output, consider switching to a TrueType font such as L ucida Console! works fine. ------------------------------------------------------------------------------------ this result means actual path byte length over run path buffer? static char path[PATH_MAX + 1]; hmmm... I'm not sure why -fno-inline-small-functions works. (2013/10/04 2:36), Erik Faye-Lund wrote: > On Thu, Oct 3, 2013 at 7:25 PM, Antoine Pelisse wrote: >> I've not followed the thread so much but, in that >> entry.c::checkout_entry,() we do: >> >> memcpy(path, state->base_dir, len); >> strcpy(path + len, ce->name); >> >> which can of course result in memory violation if PATH is not long enough. >> > > ...aaand you're spot on. The following patch illustrates it: > > $ /git/git-clone.exe mingw-checkout-crash.git > Cloning into 'mingw-checkout-crash'... > done. > fatal: argh, this won't work! > warning: Clone succeeded, but checkout failed. > You can inspect what was checked out with 'git status' > and retry the checkout with 'git checkout -f HEAD' > > --- > > diff --git a/entry.c b/entry.c > index acc892f..505638e 100644 > --- a/entry.c > +++ b/entry.c > @@ -244,6 +244,9 @@ int checkout_entry(struct cache_entry *ce, > if (topath) > return write_entry(ce, topath, state, 1); > > + if (len > PATH_MAX || len + strlen(ce->name) > PATH_MAX) > + die("argh, this won't work!"); > + > memcpy(path, state->base_dir, len); > strcpy(path + len, ce->name); > len += ce_namelen(ce); > > >> On Thu, Oct 3, 2013 at 12:26 AM, Wataru Noguchi wrote: >>> Hi, >>> >>> At last, I foundfollowing Makefile optimization suppression works fine in my >>> case. >>> >>> CFLAGS = -g -O2 -fno-inline-small-functions -Wall >>> >>> Following optimization option cause crash, >>> >>> -finline-small-functions >> -- >> To unsubscribe from this list: send the line "unsubscribe git" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html -- ================================ Wataru Noguchi wnoguchi.0727@gmail.com http://wnoguchi.github.io/ ================================ -- -- *** Please reply-to-all at all times *** *** (do not pretend to know who is subscribed and who is not) *** *** Please avoid top-posting. *** The msysGit Wiki is here: https://github.com/msysgit/msysgit/wiki - Github accounts are free. 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